Electric clock



(No Model.)

P. R. FIELD.

ELECTRIC GLOGK.

Patented Oct. 20, 1885.

Witnesses.

n4 PETERS, PhdbLlfllOgnpMr, wane-1 m". u. c.

UNITED STATES PATENT QFFIQEO FRANK R. FIELD, OF GREENFIELD,MASSACHUSETTS.

ELECTRIC CLOCK.

SPECIFICATION forming part of Letters Patent No. 328,769, dated October20, 1885.

Application filed June 1,1880.

T0 aZZ whom it may concern:

Be it known that I, FRANK R. FIELD, of Greenfield, county of Franklin,State of Massachusetts, have invented an Improvement in Electric Clocks,of which the following description, in connection with the accompanyingdrawings, is a specification, like letters on the drawings representinglike parts.

My invention relates to an electric clock of that class in which atime-measuring pendulum controls in its vibrations the circuit of anelectro-magnet, which in turn actuates an impelling device by which animpulse is given to the pendulum, and its oscillatory movement thusmaintained for an indefinite period of time.

The impulse is herein shown as derived from the force of gravity, theimpelling device consisting of a pivoted arm arranged to bear by itsweight against the pendulum during a portion of its vibratory movementin one direction, the said arm being raised or restored to its normalposition before the return movement of the pendulum by the armatureleverof an electromagnet. This magnet is shown as having two coils, one in aperma nently-closed circuit and the other in a circuit controlled by thependulum, the coils being so wound or connected that the currentspassing through both tend to neutralize one another, so that the magnetis energized with maximum effect when the circuit controlled by thependulum is broken and the current flows only through thepermanently-closed circuit.

The impelling device is supported or held in its highest position by aprop, which is disengaged from the impelling device when the latter isengaged by the pendulum-rod near the end of its vibration in onedirection, thus leaving the impelling device supported by thependulum-rod, so that its weight acts to impel the said rod during aportion of its vibration, after which the impelling device, which inthis instance directly controls the magnet, changes the condition of thelatter, causing the movement of the armature-lever, by which theimpelling device is raised or restored to its normal position and theprop placed beneath it.

When the impelling device arrives at its SerinlNo.1(l7,261. (No model.)

normal position, and is engaged and held by the prop, it again reversesthe condition of the electro-magnet, causing the return movement of thearmature, and thus leaving the impelling device free to act on thependulumrod as soon as the latter again disengages it from its prop.

The armature-lover ofthe magnet may also be employed to actuate handswhich indicate the time measured by the pendulum in the usual manner,and the main or primary clock may also control any desired number ofsecondary clocks or dials having actuating mechanism for hands, whichare thus moved in unison with those of the main or primary clock.

Figure 1 is an elevation of the mechanism of the main clock as seenlooking from the rear, the circuit being indicated in diagram; Fig. 2, aside elevation of the clock mechanism; Figs. 3 and 4, details showingthe parts in different positions, and Fig. 5 an elevation ofthemechanism ofone ofthe secondary clocks as seen from the front, thecircuit-connection between it and the main clock shown in Fig. 2 beingindicated in diagram.

The pendulum-bob a and the rod a may be of any usual construction,preferably being provided with means for compensation for variations intemperature, so that its vibrations will be as nearly as possibleisochronous, it being shown as supported on a flexible spring, (E, inthe usual manner.

The impelling device comprises an arm, I), pivoted at b at or near thepoint about which the pendulum oscillates, and a connectedsupporting-arm, b which rests on a prop orsupport, 0, until the momentarrives for imparting an impulse to the pendulum, which is done at eachalternate beat. The center of gravity of the impelling device Z: I) isat one side of its pivotal point b so that it tends to oscillate aboutthe said point. The extremity of the arm If is provided with a smallshoulder or notch, b, which receives the end of the prop c and retainsthe latter in engagement with the said arm, and the prop is itselfpivoted at c, and provided witha weight, 0, at one side of its pivot, sothat it tends to turn from beneath the arm I), as shown in Fig. 3,

when the said arm is raised so as to disengage the shoulder I) from theend of the prop.

The arm I) is provided with a projection or finger, b (best shown inFig. 2,) extending across the path of movement of the pendulumrod a, sothat the latter at the end of its oscillation toward the left, whenviewed as in Figs. 1 and 3, engages said finger If, as shown in Fig. 3,turning the impelling device slightly on its pivot, and raising the armI), and disengaging the shoulder 71" from the prop c, which then turnsfrom beneath the arm, leaving the impelling device supported by thefinger If, resting against the side of the pend ulum-rod, so that in thereturn movement of the pendulum-rod the weight of the impelling deviceis added to it and imparts an impulse sutficient to make up for theresistance from friction and other causes to the movement of thependulum. This impulse is imparted to the pendulum in its movement fromleft to right, as shown in Fig. 3, and it is necessary, in order to makethe impulse eflective, that the weight of the impelling device should beremoved from the pendulunrrod before it makes its return mo vement.

The impelling device is thus removed from the pendulum-rod and restoredto its normal position, resting on the prop, as shown in Fig. 1, bymeans of an electro-magnet, d, and its armature e, and armature-lever 0,provided with a prop-restoring projection or finger, 6

The magnet d is shown in this instance as having two coils, one in apermanently-closed circuit, 2 3, with the battery B, and the other in acircuit, 4 5 6, including the said battery, and also including theimpelling device connected with the wire 6 and a contact-piece, 0 on thearmature-lever connected with the wire 5.

The impelling device is provided with a pin or projection, I), which inthe movement of the said impelling device with. the pendulum, whichimparts its impulse thereto, comes in contact with the piece 6 thusclosing the circuit 4 5 6, through the second coil of the magnet d, thetwo coils of which are so wound or connected in circuit that when thecurrent thus passes through both its effect is neutralized on theelectro-magnet, permitting the armature e to be retracted by theretractor e, and in this retractive movement the impelling device isrestored to its normal position by the armature-lever bearing againstthe projection I), and at the same time the finger c ofthearmature-lever acts upon a spring or yielding finger, 0, connected withthe prop c, and thus tends to turn the said prop to its normal position,(shown in Fig. 1,) so that the moment the arm rises above the end of theprop the latter will be thrown beneath it by the elastic force of thespring-finger c, which has been somewhat strained by the movement of thearmaturedever. (See Fi 4.)

The movement of the prop in this direction is limited by a stop,

The movement of the armature-lever is very quick, and it thus throwstheimpelling device so that the latter will move on by its momentumafter the backward movement of the armature has been arrested by a stop,0 provided for this purpose, and will thus break the circuit at b c ofthe second coil of the magnet d, leaving the current unopposed in thepermanently-closed coil, which will thus energize the magnet with fulleffect, causing the latter to attract its armature c, and thus restoringthe parts to the position shown in Fig. 1 during thereturn vibration ofthe pendulum from right to left, at the end of which vibration. thepropelling device will again be engaged by the 11iendulum-rod and theoperations repeated, as before described.

In order to indicate the time measured by the vibrations of thependulum, the armature (I may be made to actuate suitable wheel-work orto turn the hands of the clock in any usual manner. As shown, in thisinstance the armature-lever c is provided with apawl, f, engaging theteeth of a ratchet-toothed wheel, f, which is thus caused to turn oncein a minute, and its arborf may be provided with a pointer or hand,f,(see Fig. 2,) which will thus rotate once a minute, like the secondhandof a watch or clock, and which may be made by means of suitablespeed-reducing wheel-work (not shown) to turn a minute and hour hand inthe usual manner. The pawl f is provided with-an inclined portion orlooking-cam, f", which is engaged by a stationary projection or pin, f,in. its movement, which turns the wheel f, said pin thus holding thepawl down against the wheel and preventing the latter from turningbeyond the point to which it is positively moved by the pawl. Theretaining-pawl f prevents backward rotation of the wheelf when the pawlfis moved to engage a new tooth on the wheel.

The main or primary clock shown in Figs. 1 to 4 may also be employed toactuate any number of secondary clocks placed at any desired points thatcan be connected in electric circuit with the main clock,which circuitwill include a circuit-closer operated periodically by the said mainclock.

The actuating mechanism for the hands of the secondary clock is shown inFig. 5, and comprises an eleetro-magnet, we, included in the circuit 2021 with the battery B, the said circuit also including thecircuit-closer controlled by the main clock, which consists in thisinstance of a pair of springs, a, normally insulated from one anotherand projecting into the path of the pin a, connected with the wheel f orits arbor, so that once at each rotation of the said wheel the said pinrubs over the springs a, completing the circuit between them, and thenimmediately afterward breaking the said circuit. The armaturem and itsarmature-lever m in the secondary clock is thus caused to make ato-and-fro movement by the magnet m and retractor m once at eachrevolution of the wheel f or, in other words, once a minute-and the saidarmature-lever is provided with a pawl, 0, engaging a ratchettoothedwheel, f, having sixty teeth, and provided with a retaining-pawl, 1',which prevents backward rotation while the pawl 0 is moved back by theaction of the retractor m to engage a new tooth on the ratchet. The pawl0 is provided with an arm, 0, extending along the armature leversubstantially at right angles to the movement of the pawl, and the saidarm is engaged at the end of the movement of the armature produced bythe attraction of the magnet by a stationary stop projection, 0 whichlimits the said movement, at the same time holding the pawl down betweenthe teeth of the ratchet and positively locking the same so that itcannot move too far by its momentum. A stop, m limits the backwardmovement of the armature under the action of its retractor, so that thepawl cannot be moved back over more than one tooth of the ratchet at atime.

It is not essential that the magnet (Z of the main clock should be adifferential magnet, as shown. It might contain a single coil thecircuit of which would be governed by the circuit-closer b 6 controlledby the pendulum, either closing the circuit of the said magnet andenergizing it when the members of the said circuit-closer come incontact or closing a shunt of the said magnet and thus demagnetizing it.

If the magnet were energized when the circuit was closed at 1) e itsposition with relation to the armature would have to be reversed, as thearmature-lever would restore the inipelling device and its prop in itsmovement toward the magnet instead of away from the magnet, as shown.

I claim- 1. The combination of the pendulum with an impelling device,and an electromagnet and its armature, by which the impelling device israised or restored to its normal position after an impulse has beenimparted to the pendulum, and a positive mechanicallyoperating prop orsupport for the impelling device independent of the said armature, whichprop retains the impelling device in its normal position ready to imparta new impulse independently of the movement of the armature after theimpelling device has been raised, substantially as described.

2. The pendulum and impellin g device, con sisting of two rigidlyconnected pivoted arms combined with a movable prop, which normallyengages one of the said arms, the other arm being engaged by thependulum-rod near the end of its vibration in one direction, and theprop disengaged from the impellin g device by the movement of the latterproduced by the pendulum, substantially as described.

3. The pendulum-impelling device and its prop, combined with anelectro-magnet and its armature, and armature-lever, provided with anelectric contact-piece, the impelling device having a co-operatingcontact-piece which, when it comes in contact with the armature-lever,changes the condition of the net, causing a movement ofthearmature-lever by which the impelling device is restored to its normalposition, the prop placed beneath it, and the contact-pieces separated,substantially as described.

i. A pendulum-impelling device and its pivoted prop provided with ayielding finger, combined with an electro-magnet and its armature andarmaturelever, the said impelling device and armature-lever havingco-operating contact-pieces controlling the circuit of the magnet, andthe armature-lever co-operating with the impelling device and yieldingfinger of the prop in the movement which takes place when thecontact-pieces come together, the armaturelevcr operating to raise theimpelling device and by the yielding finger to place the prop beneathit, substantially as described.

5. The pendulum-impelling device having a shouldered supporting-arm andan arm which is engaged by the. pendulum-rod, combined with a pivotedprop which engages the shouldered arm, and is weighted to fall out fromengagement therewith when the said arm is raised by the action of thependulum-rod, substantially as described.

6. In an electric clock, the pendulum and its impelling device, andelectromagnet by which the latter is restored to its normal po sitionafter an impulse has been imparted to the'pendulum, combined with a pawlhaving an inclined projection and a co-operatinglocking projection, anda ratchet-wheel actuated by the said pawl and imparting movement to thehands of the clock, substantially as dedescribed.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

FRANK R. FIELD.

Witnesses: J AMES S. GRINNELL, FREEMAN C. Gnrswom).

